1. Field of the Invention
The present invention relates to a display, especially a display capable of generating an image with uniform brightness.
2. Description of the Prior Art
Due to their slim shapes, low power consumption and low radiation, liquid crystal displays (LCDs) are widely used nowadays. When driving an LCD, a voltage difference is imposed at both ends of the liquid crystal layer to change the arrangement of liquid crystals so as to change the transmittance rate of the liquid crystal layer and to display an image.
In general, the liquid crystal display comprises a plurality of pixels, a source driver and a gate driver. The gate driver is coupled to the pixels through a plurality of gate lines, and the source driver is coupled to the pixels through a plurality of data lines, so that the gate driver can control the pixels to receive data transmitted from the source driver.
In order to reduce thickness and cost of displays, displays with reduced number of data lines have been developed. Please refer to FIG. 1, which shows a related art display 100. As shown in FIG. 1, the display 100 comprises a plurality of gate lines GL1 to GL4, a plurality of data lines DL1 to DL3 and a plurality of pixels 50. Each of the pixels 50 comprises a red sub-pixel R, a green sub-pixel G and a blue sub-pixel B. Since the number of data line of the display 100 is halved, two adjacent sub-pixels sharing the same data line must be coupled to different scan lines, so as to control the sub-pixels separately. Take the color sub-pixels in the first row for example, the first (left most) red sub-pixel R is coupled to the gate line GL1 and the data line DL1, the first green sub-pixel G next to the first red sub-pixel R is coupled to the gate line GL2 and the data line DL1, the first blue sub-pixel B next to the first green sub-pixel G is coupled to the gate line GL1 and the data line DL2, the second red sub-pixel R next to the first blue sub-pixel B is coupled to the gate line GL2 and the data line DL2, the second green sub-pixel G next to the second red sub-pixel R is coupled to the gate line GL1 and the data line DL3, and the second blue sub-pixel B next to the second green sub-pixel G is coupled to the gate line GL2 and the data line DL3. In such structure, time differences will occur when charging sub-pixels in the same row, because they are coupled to two different gate lines. This causes the levels of the previously charged sub-pixels being affected by the levels of the later charged sub-pixels. Thus, the brightness of the display 100 can not be consistent, and the display will generate the line mura effect.
Please refer to FIG. 2, which shows the waveform of light vision efficiency vs. the wavelength of light. FIG. 2 is depicted based on the International Commission on Illumination (CIE). 250 testers with normal visions are tested to generate the waveform. The waveform shows that the sensitivity of human eyes varies with the wavelength of light. In general, the wavelength of blue light is between 460 nm and 490 nm. The wavelength of green light is between 490 nm and 570 nm. The wavelength of red light is between 630 nm and 750 nm. Thus it can be seen from FIG. 2 that in these three colors, the human eye is very sensitive green light, and least sensitive to blue light.
In the second row of the display 100, the level of the green sub-pixel G coupled to the gate line GL3 and the data line DL2 will be affected by the level of the blue sub-pixel B coupled to the gate line GL4 and the data line DL2, causing the line mura effect. Unfortunately, green is the most sensitive color to human eyes, thus the image quality of the display 100 could be detrimental to users.